Motor vehicle and procedures for operating a motor vehicle

Abstract

A motor vehicle (100) comprising a traction battery (1) is proposed, wherein the motor vehicle (100) has a cooling circuit (2) for cooling the traction battery (1), wherein the cooling circuit (2) comprises a first group (10) of components and a second group (20) of components, wherein the first group (10) is arranged in a first region of the motor vehicle (100), preferably in the front region of the motor vehicle (100), wherein the second group (20) is arranged in a second region of the motor vehicle (100), which is spatially separated from the first region, in particular further rearward in the motor vehicle (100), and is directly connected to the traction battery (1), characterized in that the motor vehicle (100) is configured to, upon detection of an accident, in particular a frontal collision,to separate the first group (10) from the second group (20) and to temporarily maintain emergency operation of the cooling of the traction battery (1) using only the second group (20). Furthermore, a method for operating a motor vehicle (100) is proposed.

Description

[0001] The present invention relates to a motor vehicle with a traction battery and a cooling circuit for cooling the traction battery. The present invention further relates to a method for operating a motor vehicle.

[0002] Modern electric and hybrid vehicles feature high-performance traction batteries. The traction battery supplies energy to the vehicle's electric drive motor via the vehicle's power electronics. Especially during dynamic driving situations, i.e., situations requiring high power, but also during fast charging, the traction battery generates heat that must be dissipated.

[0003] Since cooling the traction battery, power electronics, and drive motor is often one of the performance-limiting factors in a vehicle, particular attention is paid to effective cooling. A cooling system in which the components to be cooled are directly or indirectly supplied with a coolant has become the standard. The coolant is typically a liquid, especially a cooling oil.

[0004] The coolant is circulated through the vehicle's cooling system, where it absorbs heat, particularly from components of the vehicle's high-voltage system, such as the electric motor, power electronics, and traction battery, and dissipates it into the vehicle's environment via radiators. This system requires pipes, pumps, valves, expansion tanks, and numerous other components, all of which are part of the cooling circuit.

[0005] Typically, the traction battery is located in the floor of the vehicle. The cooling circuit runs through the vehicle from the electric drive motor, for example at the rear axle, to the very front of the vehicle, where space-intensive components of the cooling circuit, in particular the radiators and coolant reservoirs, are located.

[0006] In accident situations, individual vehicle parts are often damaged, while other parts remain largely undamaged. A problem arises when the cooling system is damaged, for example, by a broken cooling line, a ruptured radiator, etc., large quantities of coolant can leak from the entire system. This not only creates environmental hazards and difficulties in recovering the wrecked vehicle, but also makes it impossible to cool the traction battery after an accident. The front of the vehicle is a particularly vulnerable area that is frequently affected and significantly damaged in accidents.

[0007] It is therefore an object of the present invention to provide a motor vehicle and a method for operating a motor vehicle which do not have the aforementioned disadvantages of the prior art, but which prevent a large part of the coolant from escaping in the event of an accident and enable makeshift cooling of the traction battery.

[0008] This problem is solved by a motor vehicle according to claim 1. Furthermore, this problem is solved by a method for operating a motor vehicle according to claim 8.

[0009] The motor vehicle according to the invention comprises a traction battery. The traction battery is designed to supply energy to an electric drive motor of the motor vehicle. The motor vehicle is therefore an electric vehicle or a hybrid vehicle. Furthermore, the motor vehicle has a cooling circuit for cooling the traction battery. The cooling circuit comprises a first group of components and a second group of components. The first group is arranged in a first region of the motor vehicle, preferably in the front region of the motor vehicle. The second group is arranged in a second region of the motor vehicle and is directly connected to the traction battery. The second region of the motor vehicle is spatially separated from the first region of the motor vehicle. In particular, it is provided that the second group is arranged further rearward in the motor vehicle.According to the invention, the vehicle is configured to separate the first cooling group from the second group upon detection of an accident, particularly a head-on collision, and to temporarily maintain emergency operation of the traction battery cooling system using only the second group. This advantageously prevents the coolant from the entire cooling circuit from escaping if the cooling circuit in the first section of the vehicle, particularly in the front section, is damaged. The separation of the first cooling group from the second group ensures that the coolant located in the second group, and especially near the traction battery, remains in the vehicle and is available for further cooling of the traction battery if the cooling circuit of the first cooling group is damaged.

[0010] The emergency cooling system for the traction battery ensures that the battery remains below a critical temperature range. For example, the coolant remaining in the second group might continue to be pumped through the traction battery without being cooled itself. The emergency operation is preferably not intended to maintain the traction battery within an optimal temperature range. Its sole purpose is to prevent damage to the traction battery due to overheating. Specifically, the vehicle is designed to have valves to interrupt the cooling circuit between the first and second groups.

[0011] Advantageous embodiments and further developments of the invention can be found in the dependent claims and in the description with reference to the drawings.

[0012] According to a preferred embodiment of the present invention, the first group of radiators is arranged in front of a crash crossmember of the vehicle, and the second group is arranged behind the crash crossmember. The area of ​​the vehicle between the front bumper and the crash crossmember is ideally suited for arranging radiators of the cooling circuit. However, in a frontal collision, this area is particularly susceptible to severe damage. The second group is further arranged in the vehicle behind the crash crossmember. The probability of damage in a frontal impact is significantly lower here. For example, it is conceivable that the second group could be arranged behind the front axle of the vehicle.

[0013] According to a further preferred embodiment of the present invention, the first group and the second group are separated by valves, wherein the valves comprise normally closed valves and / or bistable valves. Normally closed valves have the advantage that even in the event of a failure of the vehicle's 12 V supply, the valves remain closed to interrupt the cooling circuit. If the 12 V supply fails, the normally closed valves close automatically. With bistable valves, the 12 V supply must function at least until a pulse to close the valves has been generated. Once the bistable valves have closed, they remain closed even if the 12 V supply fails.

[0014] A particularly preferred embodiment of the present invention is one in which the first group and the second group are separated by pyro-valves. Pyro-valves have the advantage of closing quickly and reliably. A single closing impulse is sufficient to close the pyro-valve, which is then driven by a pyrotechnic charge and closes automatically and permanently.

[0015] According to a further preferred embodiment of the present invention, the first group comprises an expansion tank and / or a swell tank and / or a low-temperature radiator. The components of the first group are therefore the space-consuming components of the cooling circuit. For normal operation of the vehicle, expansion tanks, swell tanks, and low-temperature radiators are necessary and preferably located in the frontmost area of ​​the vehicle. In emergency operation, these components can be temporarily omitted. This makes it advantageous to arrange these components in the first group, which is separated from the second group in the event of a frontal collision.

[0016] According to a further preferred embodiment of the present invention, the cooling circuit includes a pumping device for conveying a coolant through the first group. The pumping device is configured to switch off upon detection of a frontal collision. This advantageously prevents the active expulsion of coolant through damage to the cooling circuit. While coolant may escape if the cooling circuit is damaged, it will only find its way through the damage. Because the pumping device is switched off, no further coolant is conveyed through the damage. The pumping device can, for example, be a coolant pump.

[0017] Preferably, the cooling circuit includes an additional pumping device for conveying the coolant through the second group. This additional pumping device is configured to continue pumping even after a frontal collision is detected. This advantageously ensures that the traction battery continues to be supplied with coolant. It is conceivable that, in the event of a frontal collision and after the first group is disconnected from the second, the traction battery and the second group are connected to form a separate coolant circuit. After disconnection, the coolant circulates in this separate coolant circuit for emergency cooling of the traction battery. Alternatively, the second group could have an additional low-temperature (LT) cooler for emergency cooling of the coolant. This cooler could, for example, be smaller than the LT cooler.

[0018] A further object of the present invention for solving the problem formulated at the outset is a method for operating a motor vehicle according to the invention. Upon detection of a frontal collision, the first group of components of the cooling circuit in the front area of ​​the motor vehicle is separated from the second group of components of the cooling circuit, which is located further back in the motor vehicle and directly connected to the traction battery. Furthermore, emergency operation of the cooling of the traction battery is temporarily maintained using only the second group. The method according to the invention prevents an unnecessarily large amount of coolant from escaping in the event of damage to the motor vehicle in a frontal collision. At the same time, it ensures that the traction battery of the motor vehicle can continue to be cooled, at least temporarily, in an emergency manner even after a frontal collision.

[0019] According to a further preferred embodiment of the present invention, the pumping device is switched off upon detection of a frontal collision, while the secondary pumping device remains switched off upon detection of the frontal collision. This advantageously prevents an unnecessarily large amount of coolant from being driven off due to damage to the first group caused by the operation of the pumping device. At the same time, however, it allows the traction battery to continue to be supplied with coolant. The pumping device and the secondary pumping device are preferably coolant pumps.

[0020] A particularly preferred embodiment is one in which the additional conveying device is only not switched off upon detection of a frontal collision if a waiting period has not been exceeded since an operating phase with increased cooling requirements for the traction battery. The operating phase with increased cooling requirements for the traction battery includes, in particular, fast charging and / or driving with increased power requirements. This prevents the additional conveying device from operating unnecessarily. During the waiting period, the traction battery is cooled down after the end of the operating phase with increased cooling requirements. At the end of the waiting period, the traction battery has reached its normal operating temperature and generates a normal amount of waste heat. In such a state, it is not necessary for the additional conveying device to continue operating in the event of a separation of the first group from the second group.It is conceivable that the waiting time is selected depending on the temperature of the traction battery. If the traction battery has reached its normal operating temperature, the waiting time can be set to 0 seconds.

[0021] All details, features and advantages previously disclosed in connection with the motor vehicle according to the invention also relate to the method according to the invention and vice versa.

[0022] Further details, features, and advantages of the invention will become apparent from the drawing and from the following description of preferred embodiments with reference to the drawing. The drawing merely illustrates an exemplary embodiment of the invention, which does not limit the inventive concept. Fig. Figure 1 schematically illustrates a motor vehicle according to an exemplary embodiment of the present invention.

[0023] Fig.Figure 1 schematically illustrates a motor vehicle 100 according to an exemplary embodiment of the present invention. The motor vehicle 100 is an electric vehicle with an electric traction motor (not shown). The electric traction motor is supplied with electrical energy by a traction battery 1.

[0024] During operation of the vehicle 100, the high-voltage components of the powertrain, and in particular the traction battery 1, must be cooled. A cooling circuit 2 is provided for this purpose, in which a coolant circulates. The coolant absorbs heat from the traction battery 1 and releases it at another point in the cooling circuit 2.

[0025] Cooling circuit 2 comprises a multitude of components. Since the individual components contribute little to understanding the present invention, detailed drawings have been omitted. Cooling circuit 2 includes, for example, low-temperature radiators, expansion tanks, coolant pumps, expansion tanks, lines, and heat exchangers. Many of the components of cooling circuit 2 are located in the front area of ​​the vehicle 100, for example, directly behind the front bumper. Other components are located further rearward in the vehicle 100.

[0026] If the vehicle 100 is involved in a head-on collision, there is a risk that damage to the components of the coolant circuit 2 at the front of the vehicle 100 will cause the entire coolant of the cooling circuit 2 to leak out. This not only poses a potential environmental hazard, but also prevents further cooling of the traction battery 1, as the entire cooling circuit 2 will be empty.

[0027] To prevent this, valves 3 are provided between a first group 10 of components of the cooling circuit 2 and a second group 20 of components of the cooling circuit 2. In the embodiment shown here, the first group 10 comprises the components of the cooling circuit 2 which are arranged in the front area of ​​the motor vehicle 100, in particular in front of a crash crossmember 5 of the motor vehicle 100. The second group 20 comprises the components of the cooling circuit 2 which are arranged behind the crash crossmember 5. For example, a low-temperature radiator, an expansion tank, and a swell tank are arranged in the first group 10.

[0028] If a head-on collision is detected, the valves 3 are closed, separating the first group 10 from the second group 20. The valves 3 can include, for example, pyro valves, normally closed valves, and / or bistable valves.

[0029] When the valves 3 are closed, a pumping device 4 for conveying the coolant through the first group 10 is switched off. In the embodiment shown here, the pumping device 4 is a coolant pump. This prevents coolant from being expelled from the first group 10 due to any damage to the cooling circuit 2 caused by the operation of the pumping device 4.

[0030] The second group 20, which is directly connected to the traction battery 1, includes an additional pumping device 5 in the form of a coolant pump. After the first group 10 is disconnected from the second group 20, the second group 20 is configured so that the additional pumping device 5 pumps coolant through the traction battery 1 and the second group 20 for temporary emergency operation to cool the traction battery 1. This is only executed if a certain waiting time has not yet been exceeded since an operating phase with an increased cooling requirement for the traction battery 1. If the traction battery 1 is still within this waiting time, it can be assumed that the traction battery 1 is still above its normal operating temperature or continues to produce more heat than it does under normal operating conditions.

[0031] The operation of the additional conveying unit 5 ensures that the traction battery 1 continues to be cooled during the separation of the first group 10 from the second group 20. An operating phase with increased cooling requirements could include, for example, fast charging or a phase of very dynamic driving. If the waiting time has been exceeded, it can be assumed that further cooling of the traction battery 1 is not necessary. The additional conveying unit 5 then does not ensure a coolant flow through the traction battery 1 after the separation of the first group 10 from the second group 20. Reference symbol list 1 traction battery 2 Coolant circuit 3 valve 4. Support facility 5 other funding institutions 10 first group 20 second group 100 motor vehicles

Claims

[1] Motor vehicle (100) comprising a traction battery (1), wherein the motor vehicle (100) comprises a cooling circuit (2) for cooling the traction battery (1), wherein the cooling circuit (2) comprises a first group (10) of components and a second group (20) of components, wherein the first group (10) is arranged in a first region of the motor vehicle (100), preferably in the front region of the motor vehicle (100), wherein the second group (20) is arranged in a second region of the motor vehicle (100), which is spatially separated from the first region, in particular further rearward in the motor vehicle (100), and is directly connected to the traction battery (1), characterized by, that the motor vehicle (100) is configured to disconnect the first group (10) from the second group (20) upon detection of an accident, in particular a frontal collision, and to temporarily maintain an emergency operation of the cooling of the traction battery (1) with only the second group (20). [2] Motor vehicle (100) according to claim 1, characterized by , that the first group (10) is arranged in front of a crash cross member (5) of the motor vehicle (100) and the second group (20) is arranged behind the crash cross member (5) of the motor vehicle (100). [3] Motor vehicle (100) according to any one of the preceding claims, characterized by , that the first group (10) and the second group (20) are separated by valves (3), wherein the valves (2) comprise normally closed valves and / or bistable valves. [4] Motor vehicle (100) according to any one of the preceding claims, characterized by , that the first group (10) and the second group (20) are separated by pyro valves. [5] Motor vehicle (100) according to any one of the preceding claims, characterized by , that the first group (10) has a reservoir and / or a swelling reservoir and / or a power supply cooler. [6] Motor vehicle (100) according to any one of the preceding claims, characterized by , that the cooling circuit (2) has a conveying device (4) for conveying a coolant through the first group (10), wherein the conveying device (4) is configured to switch off upon detection of a frontal collision. [7] Motor vehicle (100) according to claim 6, characterized by , that the cooling circuit (2) has a further conveying device (5) for conveying the coolant through the second group (20), wherein the further conveying device (5) is configured to continue conveying even when a frontal collision is detected. [8] Method for operating a motor vehicle (100) according to any one of the preceding claims, characterized by, that upon detection of a frontal collision, the first group (10) of components of the cooling circuit (2) in the front area of ​​the motor vehicle (100) is separated from the second group (20) of components of the cooling circuit (2), which is located further back in the motor vehicle (100) and is directly connected to the traction battery (1), and an emergency operation of the cooling of the traction battery (1) is temporarily maintained with only the second group (20). [9] Method according to claim 8, characterized by , that the conveying device (4) is switched off when the frontal collision is detected and that the further conveying device (5) is not switched off when the frontal collision is detected. [10] Method according to claim 9, characterized by, that the further conveying device (5) is not switched off when the frontal collision is detected only if a waiting time has not been exceeded since an operating phase with increased cooling requirement of the traction battery (1), wherein the operating phase with increased cooling requirement of the traction battery (1) includes in particular fast charging and / or driving with increased power requirement.